1. Field of the Invention
The present invention relates to a manufacturing method for a magnetic head, and particularly relates to a manufacturing method for a magnetic shield in which an electrode film of a plating film is reduced.
2. Description of the Related Art
A hard disk drive includes a magnetic head for recording into a hard disk, which is a recording medium, and for reading from the hard disk. Recently, because of reduction of track intervals in association with higher recording density of the hard disk, problems of adjacent track erasure (ATE) and wide area track erasure (WATE) have become obvious. The ATE is a phenomenon where magnetic information recorded in adjacent tracks is erased due to a magnetic flux from a magnetic head. The WATE is a phenomenon where magnetic information recorded not only in adjacent tracks but also in wider tracks is erased due to a magnetic flux from a magnetic head.
The ATE and WATE can be restrained by a magnetic shield provided near a main magnetic pole layer. The magnetic shield is normally made of a plating film. The ATE and WATE are further effectively restrained by optimizing a shape and materials of the magnetic shield. In the meantime, since the magnetic shield is preferably formed in proximity to the main magnetic pole layer as much as possible, the magnetic shield has a shape to protrude downwardly toward a substrate in the vicinity of an air bearing surface. Consequently, the magnetic shield is formed in a plurality of plating steps. As a result, an electrode film remains in the magnetic shield because of the plating steps. The remaining electrode film causes an unintentional magnetic flux in the adjacent tracks or neighborhood tracks from an exposed portion on the air bearing surface, causing the ATE and WATE.
A magnetic head and a manufacturing method thereof that can respond to the problems above are described in US2011/0249364. A sacrificial layer is pre-formed on the main magnetic pole layer. The sacrificial layer is provided from a position to be an air bearing surface to another position away from the air bearing surface by a predetermined distance in a vertical direction. Next, an insulation layer is formed behind of the sacrificial layer viewing from the air bearing surface. After a coil is formed, the sacrificial layer is removed, and a plating film is formed. With this step, the plating film having a front end portion protruding downward on the air bearing surface can be formed in one plating step, and any remainder of the electrode film between the plating films is prevented.
However, these steps require three steps, which are to provide the sacrificial layer, to provide the insulation layer behind that layer, and then to remove the sacrificial layer.
An objective of the present invention is to provide a manufacturing method for a magnetic head in which an electrode film exposed to the air bearing surface does not remain in the magnetic shield composed of a plating film, and in which the magnetic shield is formed with simple steps.